The idea for this activity also comes from Game Plan but the visual is one I made myself. After singing the melody, I would play a high/low sound on the glockenspiel (the instrument we have been working on playing) and a student would place the leaf on the visual. It took about 7 minutes to give everyone a turn but singing in between helped keep them from getting restless.
I like to pair an activity like this with some movement because little bodies can only take so much sitting. After we did this, we sang another song about leaves and created movement to go along with it.